Why is bill ayers still a free man?

this man is a terrorist he and his weather underground gang blew up a Police station in new york and the pentagon and a united states capitol and bill ayers goes on t.v and brags about this and how proud he is for what he did . to all you parents out there he is now or was a teacher [ i think he retired [ and bill ayers and obama are good friends i know Obama denys this but they know each other before obama was elected to the office in o8 obama meet bill ayers in college trust me there friends obama can deny it all he wants